Japanese Nuclear Accident Simulations Severely Underestimate Radiation Risks

Press release - 29 November, 2011
Tokyo, Japan, November 29, 2011 – Greenpeace today renewed its demand for the Japanese government to keep its nuclear reactors offline as simulation maps of potential accidents at Japan’s nuclear plants - used in the development of nuclear emergency response efforts - are completely inadequate, and have not been updated since the Fukushima disaster.

Following a Greenpeace freedom of information request on November 25, the Ministry of Education, Culture, Sports, Science and Technology (MEXT) released SPEEDI simulations of the radioactive contamination spread from all nuclear plants in Japan (1). These maps show only extremely low releases of radioactivity over a 10km area around the plants in the event of meltdown, making any emergency response plan based on them totally insufficient should another severe disaster like the Fukushima Daiichi crisis occur (2).

“The simulation of radioactive releases from the Ohi reactor for example, is scandalously inadequate. It foresees a radiation release in the order of 10,000 times less severe than what could happen during a major incident (3),” said Jan Vande Putte, Greenpeace International Nuclear Campaigner. “Similar over-optimistic scenarios have been used for reactors all over Japan. Hoping for the best is absolutely the wrong way to devise an emergency response plan.”

Greenpeace met with officials from MEXT and the SPEEDI programme today, and they confirmed that the current simulations are limited to low-level releases, and that the system needed upgrading to cover larger releases and wider areas beyond 10km from the plants.

“The Fukushima Daiichi emergency response effort was slow, chaotic and insufficient, and it appears the Government has learned nothing from it so far,” said Junichi Sato, Greenpeace Japan Executive Director. “These maps show that there is a strong risk of reactor restarts being pushed through without a proper, science-based assessment on the real risks being conducted, and without proper precautions being taken to protect the communities around the plants.”

Greenpeace is demanding that the Japanese government uses SPEEDI for what it was developed for, and run worst-case scenario simulations for all nuclear plants in Japan so there is a clear understand what effect a Fukushima Daiichi-type incident at other plants around Japan could have.

ENDS

Greenpeace is an independent global campaigning organisation that acts to change attitudes and behaviour, to protect and conserve the environment, and to promote peace.

Contacts:
Greg McNevin, Greenpeace International Communications, , +81 80 5416 6507
Yuki Sekimoto, Greenpeace Japan Communications, , +81 80 5088 3048
Greenpeace International Press Desk Hotline, Amsterdam +31 20 7182470

Notes:
1) The simulations released under FOI to Greenpeace were made to support emergency preparedness drills of local and central government authorities. They calculate the concentration of radioactivity in the air, contamination on the ground and dose to the population within a range of 10km. Based on these maps, drills on evacuation or sheltering of the population, or distribution of iodine pills are organised.

Published maps (Japanese only): http://www.bousai.ne.jp/vis/speedi_z/

2) Greenpeace has measured contamination levels high enough to require evacuation under international standards at 60km distance from Fukushima Daiichi www.greenpeace.org/fukushima-data

3) A major incident in this case is based on a 15% release of iodine from the core of the reactor, which is still not a worst-case scenario. Nuclear safety authorities from the United States (NRC, Nureg-1150, 1990) and Germany (SSK, Heft 37, 2003) have calculated that under the worst-case conditions, even a release between 50% and 90% of all iodine is possible, though with a lower probability.

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